Answer:
Explanation:
a) To get the resistivity ρ at 50 Celsius, given the resitstivity at 20 Celsisus, use:
ρ = ρo(1 + α(T - To))
where To = 20 Celsius
b) Knowing the resistivity at 50 Celsius, and the (uniform) electric field E, you can determine the current density J using:
E = ρJ
(which is actually a density-averaged version of V = IR)
c) Assuming the current is uniform (which is should be in a uniform electric field and constant-diameter wire), the current i can be calculated using:
J = i/A --> i = JA
where A is the cross-sectional area of the wire (given by πr2); make sure to convert the given diameter to a radius, and the radius to base units
d) Since the electric field is given in volts per meter, and you have two meters of length in the wire, you can determine directly from that how many volts difference you need at the ends of the wire to get 0.2 volts per meter.
0.2 = V/d
with d = 2 m. This corresponds to a uniform electric field being related to voltage by V = Ed, where d is distance along the field line.
Answer metalloids hope this helps
<em>Answers:</em>
<em>1. The hot soup will loose the heat and the ice water will gain the heat</em>
- If two jars are insulated inside the insulated box, the heat may not be transferred to outside of the box.
- According to II law of thermodynamics, Heat always flow from high temperature body to low temperature body, with out aid of external energy.
<em>So, from two points, it is concluded that The hot soup will lose heat and the ice water will gain the heat until they reach the thermodynamic equilibrium.</em>
<em>2. The particles in gases are farther apart and move faster </em>
- Particles in the gases are loosely packed (greater distance between particles compared to solids and liquids) and particles collide less often.
<em>Therefore conduction is weak in gases compared to solids and liquids.</em>
<em>3. Heat and milk by conduction; popping popcorn by radiation.</em>
- The heat can transfer from pot to the milk by conduction because they are in contact at boundaries, similarly the pot and the stove are in contact <em>so the conduction transfers heat from pot to the milk. </em>
- In microwave oven there is no direct contact (<em>no conduction</em>) of heat and popcorn, also there is no molecular momentum transfer <em>(means of no convection).</em>
<em>So obviously the heat transfer by radiation occurs in a microwave oven.</em>
Answer: C) Label 1: X
Label 2: Z
Explanation: Conductors are those substances which conduct electrical current easily because of the presence of free electrons whereas Insulators do not conduct electrical current as they do not contain free electrons. Some common examples of conductors are copper, aluminum, gold, and silver. Some common examples of insulators are glass, air, plastic, rubber, and wood.
Label 1: Lacks free electrons must be placed in the area marked X as they correspond to insulators.
Label 2: Aluminum is an example of conductor and thus must be labelled in area marked by Z.
Area Y corresponds to semiconductors which have properties intermediate to conductors and insulators.
